1. Field of the Invention
The present invention generally relates to devices for securely aligning a syringe with a vessel containing an injectable medication.
2. Description of the Related Art
The treatment of conditions requiring frequent injections of medications, such as insulin for the treatment of diabetes, has traditionally demanded that a user purchase vial of medication, often 10 ml in volume, draw a dosage from the vial using a syringe, and store the remaining medication in a refrigerated environment until a subsequent injection is needed.
Alternatively, a user can purchase a variable volume cartridge, typically 1.5-3.0 ml in volume, as disclosed in U.S. Pat. No. 5,334,162, assigned to the assignee of the present invention. Such cartridges typically contain only a few dosages, and are sold pre-enclosed in an injector pen which is disposed of after the medication is dispensed.
In certain locations throughout the world, both of the aforementioned alternatives present difficulties. In locations where access to refrigeration is scarce or simply unavailable, a 10 ml vial is not a viable option because medication remaining in the vial cannot be properly maintained. Moreover, the purchase of the larger, 10 ml vial, itself, is often beyond the economic means of the potential user.
Given the expense of vials, as well as the unavailability of adequate refrigeration in many locations, the less expensive and smaller variable volume cartridge is especially desirable. However, since such cartridges are typically sold encased in a disposable injector pen, the cost of the unit as a whole is often too great for many potential users.
Not only are vials relatively expensive and difficult to maintain, but vials also require a user to hold the vial in one hand and insert the needle of a syringe into the vial with the other hand during the dosing process. This procedure, while adequate for some, is subject to mistakes such as needle pricks or inaccurate dosages and is particularly a problem for patients having unsteady hands, persons who are visually impaired, or for children.
The prior art has attempted to address this problem by providing a tool which guides the syringe needle directly into the opening of the vial. For example, U.S. Pat. No. 5,240,047, issued to Hedges, discloses a one-piece needle guide and bottle holding device in which one channel of the device is adapted to receive a portion of the bottle or vial such that the opening of the vial is exposed to the needle guide channel.
While a device such as Hedges is adequate for aligning a syringe with a vial, variable volume cartridges are much smaller and differently shaped than vials, and therefore the Hedges design will not function with variable volume cartridges. The aforementioned U.S. Pat. No. 5,334,162 does disclose a device which can be attached to a variable volume cartridge and receive a syringe therein, but the device is designed for injecting fluid into a cartridge, and not inexpensively and accurately aligning a syringe with a cartridge for subsequent extraction of fluid from the cartridge.